This is really cool (I've been wondering how to do a string-switch for a while now), but I don't think getopt is a great use case, because getopt still results in imperative argument parsing and this always results in pain.
I've been working on libargs for the past year; it's a declarative argument-parsing library for C: https://github.com/mcinglis/libargs
The main idea is that each argument is by default parsed and stored as a string, or you can optionally specify a function of the type `void f(char * name, char * arg, void * dest)` to parse the argument string and store it in a well-typed destination. This way, you can have an `int` argument by passing `int__argparse` as the parser, and if the user passes a value outside the range of `int`, then an appropriate out-of-range error is printed to the console. Similarly with `uchar__argparse` or something like `point__argparse` (e.g. taking some format like `{x,y}`).
libargs is quite flexible and has worked well for me so far. Automatic help text generation can be added in future while maintaining (non-ABI) backwards compatibility.
The main disadvantage is that it depends on other libraries I've developed that are essentially Jinja-templated C source files that function as makeshift generic types / typeclasses in C. Your inclination towards this approach depends on taste; personally I much prefer deferring the pain to the build system, as opposed to the source code.
I've been working on libargs for the past year; it's a declarative argument-parsing library for C: https://github.com/mcinglis/libargs
The main idea is that each argument is by default parsed and stored as a string, or you can optionally specify a function of the type `void f(char * name, char * arg, void * dest)` to parse the argument string and store it in a well-typed destination. This way, you can have an `int` argument by passing `int__argparse` as the parser, and if the user passes a value outside the range of `int`, then an appropriate out-of-range error is printed to the console. Similarly with `uchar__argparse` or something like `point__argparse` (e.g. taking some format like `{x,y}`).
libargs is quite flexible and has worked well for me so far. Automatic help text generation can be added in future while maintaining (non-ABI) backwards compatibility.
The main disadvantage is that it depends on other libraries I've developed that are essentially Jinja-templated C source files that function as makeshift generic types / typeclasses in C. Your inclination towards this approach depends on taste; personally I much prefer deferring the pain to the build system, as opposed to the source code.